Question

The strength of an acid depends on the concentration of the hydronium ions ________ present in a solution.
(A) ${H^ + }$
(B) ${H_3}{O^ + }$
(C) $O{H^ - }$
(D) All of the above

Answer 1

Hint : In aqueous solution, a hydrogen ion is nothing more than a proton, a bare nucleus. Despite the fact that it only contains a single unit of positive charge, this charge is condensed into a volume of space only a hundred millionth the size of the tiniest atom. The proton is strongly attracted to any portion of a surrounding atom or molecule with an excess of negative charge as a result of the proton's extremely high charge density.

Complete Step By Step Answer:
The ease with which an acid loses a proton is referred to as the acid's strength. In an aqueous solution, a strong acid ionises fully by losing one proton. The concentration of hydronium ions in the water is equal to the entire concentration (ionised and unionised) of the acid added to solution due to full dissociation of strong acids in aqueous solution. Hydronium is a cation that develops when hydrogen ions are present in water. These hydrons are very reactive and are solvated by water. Hydrons are usually produced by an acidic solute, although they can also be found in pure water. The self-ionization of water refers to the process of water interacting with water to create hydronium (and hydroxide) ions. The hydronium ions that arise are few and short-lived. The relative activity of hydronium and hydroxide ions in aqueous solutions is measured by pH. Hydronium is more active in acidic solutions because its extra proton is easily available for interaction with basic species.
Consider
$HCl + {H_2}O \to {H_3}{O^ + } + C{l^ - }$
The degree of dissociation determines the strength in acid. The degree of dissociation is determined by the concentration of the product.
As a result, ${H_3}{O^ + }$ is affected by the acid's strength and vice versa.

Hence the final answer is (B).

Note :
The hydronium ion should be referred to as oxonium according to the IUPAC nomenclature of organic chemistry. Hydroxonium can also be used to identify it without ambiguity. In addition, a draught IUPAC proposal suggests using oxonium and oxidanium in organic and inorganic chemistry, respectively. Any ion having a trivalent oxygen cation is an oxonium ion. A protonated hydroxyl group, for example, is an oxonium ion but not a hydronium ion.